Refactor(Structure): Move ADTs into adt/ folder, rename spel.rkt to main.rkt

New structure groups all ADT modules under adt/ directory, removing
redundant adt- prefix from filenames. Library names now read as
(pacman-project adt position) etc. All imports updated accordingly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pacman-project/adt/score.rkt

@@ -0,0 +1,32 @@
+#lang r7rs
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;                                Score ADT                                  ;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;; Tracks the player's score. Contains NO graphics code.
+
+(define-library (pacman-project adt score)
+  (import (scheme base)
+          (pacman-project constants))
+  (export make-score)
+
+  (begin
+
+    ;; make-score :: -> score
+    ;; Creates a new score object, starting at 0.
+    (define (make-score)
+      (let ((points 0))
+
+        ;; increase! :: -> /
+        ;; Increases the score by points-per-coin.
+        (define (increase!)
+          (set! points (+ points points-per-coin)))
+
+        ;; dispatch-score :: symbol -> any
+        (define (dispatch-score msg)
+          (cond ((eq? msg 'points) points)
+                ((eq? msg 'increase!) increase!)
+                (else (error "Score ADT -- Unknown message:" msg))))
+
+        dispatch-score))))